annelid

annelid

any of a phylum (Annelida) of roundish, wormlike animals having long, segmented bodies, a brain and ventral nerve cord, and a closed circulatory system, including polychaetes, oligochaetes, and leeches

Origin of annelid

; from Modern Latin Annelida (pl.) ; from French annélides ; from (animaux) annelés, ringed (animals) ; from past participle of anneler, to encircle ; from Old French anel, a ring ; from Classical Latin annellus, diminutive of anulus, a ring: see annular

of this phylum

annelid

noun

Any of various worms or wormlike animals of the phylum Annelida, characterized by an elongated, cylindrical, segmented body and including the earthworms and the leeches.

Origin of annelid

From New Latin Annelida, phylum name, from French annelés, pl. past participle of anneler, to ring, from Old French anel, ring, from Latin anellus, diminutive of anus, ring.

Sentence Examples

In this Annelid later the sac in question joins its fellow, passing beneath the nerve cord exactly as in the leech, and also grows out to reach the exterior.

Relationships And Phylogeny The Hexapoda form a very clearly defined class of the Arthropoda, and many recent writers have suggested that they must have arisen independently of other Arthropods from annelid worms, and that the Arthropoda must, therefore, be regarded as an " unnatural," polyphyletic assemblage.

Pharynx, and he sums up their relationship to the Annelids by thestatement that to a certain extent the Nemertines represent Turbellaria which in the course of time have copied certain features of an Annelid character.

This annelid propagates its kind by rising to the surface and dividing itself.

In descending order they embrace the following subdivisions, whose thickness in the district of Durness is estimated at about 2000 ft.: (e) limestones, dolomites and cherts, with numerous organic remains; (d) grit and quartzite, with Saltarella and Olenellus (Serpulite Grit); (c) calcareous shales and dolomites, with many annelid casts and sometimes Olenellus (Fucoid Beds); (b) Upper Quartzite, often crowded with annelid pipes (Pipe Rock Quartzite); (a) Lower Quartzite - their original upper limit can nowhere be seen, for they have been overridden by the Eastern Schists in those gigantic underground disturbances already referred to, by which these rocks, the Archean gneiss and Torridonian sandstone, were crumpled, inverted, dislocated and thrust over each other.